Segment information - Summary of Activity by Segment (Details) - USD ($) $ in Millions	3 Months Ended
	May 04, 2019	May 05, 2018	Feb. 02, 2019
Segment Reporting Information [Line Items]
Sales	$ 1,431.7	$ 1,480.6
Operating income (loss)	(2.6)	(574.2)
Restructuring costs	26.8	6.5
Goodwill and intangible impairments	0.0	448.7
Credit transaction, net	0.0	141.0
Total assets	6,193.3	5,272.9	$ 4,420.1
North America
Segment Reporting Information [Line Items]
Sales	1,300.3	1,347.8
Operating income (loss)	48.1	(537.3)
Restructuring costs	(0.5)
Goodwill and intangible impairments		448.7
Credit transaction, net		141.0
Total assets	5,437.4	4,722.3	3,943.0
International
Segment Reporting Information [Line Items]
Sales	111.5	128.7
Operating income (loss)	(8.0)	(7.6)
Total assets	608.1	401.7	367.4
Other
Segment Reporting Information [Line Items]
Sales	19.9	4.1
Operating income (loss)	(42.7)	(29.3)
Restructuring costs	27.3	6.5
Total assets	$ 147.8	$ 148.9	$ 109.7